FactorySemantics MES

An open-source, modular, agent-native Manufacturing Execution System.

Run one module on a laptop for a five-person shop, or the full suite across a fleet of plants. Every capability is an API and an agent tool first, a screen second. Every number is honest about where it came from.

Status: pre-alpha, running simulated plants only (as of 2026-09-07). Orders and routings, OPC UA execution, OEE, quality with SPC and gauges, maintenance, finite-capacity scheduling, serialisation and genealogy, an 85-tool MCP agent surface, an ERPNext connector, and a scoring harness that measures whether the MES told the truth about its plant. The largest simulated plant is an 83-station cutlery works serialising every piece (labs/cutlery); it is the public demo. Not yet: a real plant in production, the per-operation ERP contract end to end (M7), plant packs as a product (M8), and PLC write-back beyond a guarded recommendation queue. See ROADMAP.md for what has landed and what is next, docs/ARCHITECTURE.md for the design, docs/LANDSCAPE.md for why this project should exist at all, and docs.factorysemantics.com for the documentation.

Nothing on this page is measured on a real plant. Every number in this repository comes from a simulated line and says so where it appears.

Why this exists

Three facts, verified 2026-08-28 (sources in docs/LANDSCAPE.md):

1. No integrated open-source MES exists. ERP projects (Odoo, ERPNext, Qcadoo) stop at work orders — no machine connectivity, no OEE, no SPC. Data-infrastructure projects (United Manufacturing Hub, Rhize) deliberately refuse to be the MES. SCADA projects have machine data but no manufacturing semantics. Nothing open-source does gauge/calibration management at all. Plants that can't afford a €200k–1.5M commercial MES implementation stitch together Node-RED, Grafana, and spreadsheets — and the ERPNext maintainers themselves published the missing-features list (erpnext#50827).

2. The agent-native lane is open, but the window is closing. Every incumbent (Siemens, Bosch, Rockwell) is bolting AI agents onto closed platforms. Tulip shipped an MCP server; Ignition announced one for 2026. An MES whose core is designed to be operated by agents — permissioned writes, append-only audit, semantic events — with the source open, has no occupant.

3. This isn't starting from zero. The kernel came from a working, tested mini-MES (orders, routings, OPC UA machine layer, OEE, ERPNext round-trip) that was merged into this repository on 2026-08-31. The test plant is a deterministic line simulator that lives in src/fsmes/sim/. See Provenance below.

The north star

Siemens Opcenter-level functional coverage, as open-source modules on one kernel. The table is the target; the marks say how far each item has come as of 2026-09-02 (✅ landed · 🟡 partial · ⬜ not started):

Honesty about scale: Opcenter is thousands of engineer-years. The path here is not cloning it — it's shipping the 20% of each module that covers 80% of a small-to-mid plant, correctly and honestly, module by module, with agents as the force multiplier. Depth grows where users pull.

Principles

1. Kernel + modules. A small kernel (master data, orders, routing, dispatch, execution, events, audit, auth) that is always present; everything else — quality, maintenance, scheduling, gauges — is an optional module. A customer installs only what they need.
2. Standards-shaped, not standards-burdened. ISA-95 nouns for the data model, PackML for machine states, ISO 22400 for KPIs, B2MML only at the ERP border. Never invent a word the industry already has; never implement an XML schema internally.
3. Agent-native. Every function callable via REST and MCP. Read tools are free; command tools are idempotent, support dry_run, and pass approval gates. Agents act on behalf of an identified human, and every action — human or agent — lands in the same append-only audit spine.
4. Never invent production. Counter deltas book production; resets re-baseline and book nothing. OEE reports unknown, never a misleading zero. Unlabelled downtime is reported as unlabelled. Every screen states its data source.
5. Runs anywhere. SQLite on a laptop → Docker Compose in a plant → fleet of nodes with a console. Operator UI is plain HTML/JS with no build step, because a plant PC must render it for years without a node toolchain.
6. Simulation-first. CI runs a full fake plant (deterministic six-station line over a real OPC UA server). Every feature is demoable without hardware. Scripted failures — breakdowns, changeovers, counter resets, micro-stops — are named regression tests.
7. Config, not code, at every plant boundary. Which tags a machine exposes lives in a tag map. What a plant enables lives in a plant pack. A second, deliberately-different demo pack exists purely to prove that adding a plant never requires a code change.

Provenance — where the code comes from

This project is a convergence, and its origins are recorded deliberately:

Clean-room rule: everything here derives from the personal projects above, public standards, and public documentation. Nothing derives from any commercial MES's internals, schemas, or documentation, and no employer data or configuration is ever committed. Domain understanding from running an MES daily informs what to build; proprietary material does not enter this repository.

The FactorySemantics family

• FactorySemantics MES (this repo) — the execution layer: runs the floor, books production, owns the audit trail.
• FactorySemantics — the semantic layer: canonical events and ontology this MES is designed to emit (not yet published; see Provenance).
• factorysemantics.com — the commercial layer: on-prem analytics/ML nodes and the fleet console that consume those events.

The MES makes the data; the semantic layer names it; the intelligence layer learns from it.

Decisions (ratified 2026-08-28)

Getting started

Install from PyPI into an isolated environment and run the built-in story: one order released against a routing, run down a simulated six-station line over a real OPC UA server, booked honestly, and completed.

pipx install factorysemantics-mes   # or: uv tool install factorysemantics-mes
fsmes info
fsmes demo

From a checkout, on Linux or macOS:

python -m venv .venv && .venv/bin/python -m pip install -e ".[dev]"
.venv/bin/fsmes info
.venv/bin/python -m pytest

On Windows (plant PCs are Windows, and CI proves it):

python -m venv .venv; .venv\Scripts\python -m pip install -e ".[dev]"
.venv\Scripts\fsmes info
.venv\Scripts\python -m pytest

What runs today (2026-09-07): simulated plants from a registry (fsmes plant all start), each a complete MES over a real OPC UA server with its operator screens; fsmes score <plant> replays a scripted hour and reports whether the MES booked what the line produced, whether a planned stop was misbooked as downtime, and whether the scripted breakdown was detected; two MCP servers (the product's 85 tools, the simulator's 13). The test suite is the gate, and CI runs it on Linux and Windows.

The public demo at demo.factorysemantics.com is the cutlery plant from labs/cutlery, simulated, serving a copy of one scored hour. Nothing there is a real factory.

Where things are